Why is there the videos for Garen Sona Vi and Zed???

They were for the new champion release, Jhin. Look at his spotlight for more info.

Garen because Jhin considers him and Katarina to be the duet for his magnum opus of a tragic love story. Zed because apparently, Jhin had intricate plans for Zed's master, and he absolutely detests Zed for killing him before he could play them out. Sona, because apparently, Jhin somehow considers her musical prowess is overshadowing his artistic spotlight (despite the fact that she'd be in the Entertainment section of the papers, and he'd be headlining the Crime Reports section.) And Vi because who knows. There's absolutely no connection to Jhin and Vi in anything, no quotes, jokes, or taunts. So that's a mystery.